As the number of television channels available through various program delivery methods (cable TV, home video, broadcast, etc.) continues to proliferate, the demand for programming, particularly high-quality ItDTV-format programming, presents special challenges, both technical and financial, to program producers. While the price of professional editing and image manipulation equipment continues to increase, due to the high cost of research and development and other factors, general-purpose hardware, including personal computers, can produce remarkable effects at a cost well within the reach of non-professionals, even novices. As a result, the distinction between these two classifications of equipment has become less well defined.
The parent to this application, for example, describes a video production system which integrates equipment supplied by various manufacturers, enabling a consumer to produce and edit video material using an enhanced personal computer. An adapter unit interfaced to each camera in use with the system connects to a camera interface module, and each camera interface module, in turn, feeds a computer interface unit. These computer interface units communicate with a personal computer over a standard interconnect, allowing an operator to control the various cameras while viewing individual video programs which appear in separate "windows" on the computer monitor.
This related invention solves many of the problems associated with combining commercially available hardware to create an economical personal-computer-based system capable of very high quality audio/video production. However, the variety of available and planned program standards and delivery methods places further demands on video production equipment, including the editing and manipulation of images not only from a variety of sources, but in differing pixel formats, frame rates, and so forth. Although general-purpose PC-based equipment may never allow professional-style rendering of images at full resolution in real-time, each new generation of microprocessors enables progressively faster, higher-resolution applications. In addition, as the price of memory circuits and other data storage hardware continues to fall, the capacity of such devices has risen dramatically, thereby improving the prospects for enhancing PC-based image manipulation systems for such applications.
In terms of dedicated equipment, attention has traditionally focused on the development of two kinds of professional image-manipulation systems: those intended for the highest quality levels to support film effects, and those intended for television broadcast to provide "full 35 mm theatrical film quality," within the realities and economics of present broadcasting systems. Conventional thinking holds that 35 mm theatrical film quality is equivalent to 1200 or more lines of resolution, whereas camera negatives present 2500 or more lines. As a result, image formats under consideration have been directed towards video systems having 2500 or more scan lines for high-level production (such as the Kodak "Electronic Intermediate" system described by Hunt et al.), with hierarchies of production, HDTV broadcast, and NTSC and PAL compatible standards which are derived by down-converting these formats. Several techniques have been described, including those of Bretyl ("3.times.NTSC `Leapfrog` Production Standard for HDTV", SMPTE Journal, March 1989), Demos ("An Example Hierarchy of Formats for HDTV", SMPTE Journal, September 1992), and Lim ("A Proposal for an HDTV/ATV Standard with Multiple Transmission Formats", SMPTE Journal, August 1993). Most proposals employ progressive scanning, although interlace is considered an acceptable alternative as part of an evolutionary process. In particular, Demos addresses the important issue of compatibility to computer-graphics-compatible formats, although he begins with an 1152-line format, and only considers progressive scanning. And, as pointed out by Thorpe et al., progressive scanning also has drawbacks, and as shown by Kaiser et al. ("Resolution Requirements for HDTV Based Upon the Performance of 35 mm Motion-Picture Films for Theatrical Viewing", SMPTE Journal, June 1985), even 35 mm theatrical film quality is a misnomer since the realities of mechanical projection systems restrict the typical screen display to less than 700 TV lines/picture height.
Current technology directions in computers and image processing should allow production equipment based upon fewer than 1200 scan lines, with picture expansions to create a hierarchy of upward-converted formats for theatrical projection, film effects, and film recording. In addition, general-purpose hardware enhancements should be capable of addressing the economic aspects of production, a subject not considered in detail by any of the available references.